Nano-emulsion formulation of nematode egg parasitic fungus, Pochonia chlamydosporia to control Meloidogyne incognita infecting tomato

A new nano formulation of the nematode egg parasitic fungus Pochonia chlamydosporia was developed and evaluated against root-knot nematode, Meloidogyne incognita on tomato. Initially, sunflower oil-based nanoemulsions were prepared by the process of sonication, i.e. the high-energy method. The emulsion contained 1% w/v carboxyl methyl cellulose (aqueous phase): sunflower oil (continuous phase): Tween 80 (surfactant) at 1: 0.5: 0.125 ratio. The emulsion was stable without phase separation for up to 8 weeks at room temperature (28 +/- 4 degrees C) and 4 degrees C. Various aggregation tests such as particle size, zeta potential, and transmission electron microscopy (TEM) analysis revealed that nanoemulsion had spherical shape particles with mean particle size 226.6 +/- 1.1 nm and mean zeta potential of -54.80 +/- 0.5 mV. The nanoemulsion formulation of P. chlamydosporia was derived by homogenising of emulsion with the spore suspension at a 1:1 v/v ratio. The egg parasitisation and juvenile mortality bioassays were carried out using the developed nanoemulsion of P. chlamydosporia under in vitro conditions. Exposure of eggs and juveniles to different level of concentrations in laboratory condition caused up to 100% parasitisation of M. incognita eggs and 96% juvenile mortality. Under glasshouse conditions, soil treatment with nanoformulation of P. chlamydosporia at 0.25-5.0 mL/L lead to reduce M. incognita populations in soil by 62.2-67.9% and in tomato root by 57.4-62.1%. Pochonia chlamydosporia nanoformulation treatments caused improvement of tomato plant growth with 19.5-34.2%, 24.5-48.4%, 16.9-38.5% and 25.6-46.6% increase of shoot length, root length, shoot weight and root weight, respectively.

Automated summary

A new nano formulation of Pochonia chlamydosporia, a parasitic fungus, was developed and evaluated for the control of Meloidogyne incognita, a root-knot nematode, on tomato plants. The stable nanoemulsion, prepared using sunflower oil, showed effective parasitization and mortality of nematode eggs and juveniles, both in vitro and under greenhouse conditions. The treatment with the nanoformulation resulted in significant reduction of nematode populations in soil and improved tomato plant growth.